1. Field of the Invention
The present invention relates to a laminated capacitor and a method for manufacturing the same. More specifically, the present invention relates to a laminated capacitor with low equivalent series inductance (hereinafter abbreviated as ESL) and a method for manufacturing the same.
2. Description of the Related Art
Because supply voltage fluctuation considerably affects the operation of CPU or the like, a laminated capacitor has been disposed in the vicinity of CPU as means for suppressing supply voltage fluctuation to stabilize power supply.
In recent years, however, current fluctuation is becoming faster and greater with increase in operating frequency of CPU. This increases the effect of ESL of the laminated capacitor itself, causing a possibility that the total inductance including ESL of the laminated capacitor itself will affect the supply voltage fluctuation.
As a technology of reducing ESL, for example, Japanese Unexamined Patent Application Publication No. 2004-172602 discloses a laminated capacitor comprising first and second capacitors. The first capacitor has low ESL because opposite electrodes, which are embedded in a dielectric body, are connected to terminal electrodes, which are formed on a surface of the capacitor, via many through conductors; the second capacitor has large capacity because opposite electrodes, which are embedded in a dielectric body, are connected one another via a few through conductors.
In the laminated capacitor disclosed in JP 2004-172602, however, the first capacitor has a complicated structure with the many through conductors connected to the opposite electrodes. Therefore, the first and second capacitors have to be prepared separately and assembled later, which makes the laminated capacitor difficult to manufacture.
In addition, if the first and second capacitors are prepared separately and assembled later, a ceramic layer located on a lower surface of the first capacitor and a ceramic layer located on an upper surface of the second capacitor will be joined together to double the ceramic layer thickness at the joint between the first and second capacitors. The increase in ceramic layer thickness makes it difficult to reduce the thickness of the laminated capacitor and increase the capacity of the laminated capacitor.